code: def test_function_sampler_identity(X, y):
      sampler = FunctionSampler()
      X_res, y_res = sampler.fit_resample(X, y)
      assert_allclose_dense_sparse(X_res, X)
      assert_array_equal(y_res, y)
  
file_path: imbalanced-learn/imblearn/tests/test_base.py
imports: import numpy
  import pytest
  from scipy import sparse
  from sklearn.datasets import load_iris, make_regression
  from sklearn.linear_model import LinearRegression
  from sklearn.utils import _safe_indexing
  from sklearn.utils._testing import assert_allclose_dense_sparse, assert_array_equal
  from sklearn.utils.multiclass import type_of_target
  from imblearn import FunctionSampler
  from imblearn.datasets import make_imbalance
  from imblearn.pipeline import make_pipeline
  from imblearn.under_sampling import RandomUnderSampler
label_desc: Use image node_id 2 for calling a global function with example usage: test_function_sampler_identity(X, y) without return types